Fuel pump



April 25, 1944.

FUEL PUMP Filed Aug. 8, 1942 F -l F95 1:1 24* B 8 5' 43 Q. 5- 1 Q 63 I INVENTOR.

1.. o. FRENCH 2,347,551

constantstroke actuator andthe plunger. cording to the present invention, I use a toggle Patented Apr. 25, 1944 UNITED STATES EPATE N T OFFICE FUELPUMP "Louis 0. French, Milwaukee, Wis. Aprilication'AugustB, 1942, Serial No. 454,095

'7 Claims.

The invention relates to fuel pumps. Thegeneral object of the'invention is to providea fuel pump of the variable stroke ty pe in which the pump'p'lunger at less than full load One special object of the presvariable stroke drive connection between the linkage as a drive connection and a shiftable regulator-to' controlthe breaking of the toggle joint at different pointsin 'theistrokeof the actuator ing application Serial No. 368,763, filed April 4,

1941, and the parts are thus subjected 'to less hard wear, and this wear is distributed over a greater surfacerarea.

I A furthenobjeotwf the ei'nventlonis to provide a-fuelpump having a variable stroke plunger with means for *rotating the plunger 1to var'ythe tiine of the beginning of fuel injection. I

,The invention further consists in the several features hereinafter. set 1 forth and moreipa'rticularly. defined by claims at'the-conclusionhereof.

In the drawing:

Fig. .1 is a vertical sectional "view through a fuel .pump embodying the invention;

Fig. 2 is .a detail vertical sectional view taken on theline 2-.2 of Eig. '1;

Fig. 3 is a detail view of the operating.'linkage inan intermediate .position; '1

Fig. 4 is ,aplan view of one of -the-links';; Fig, 5 isa detail viewpf the control:rner'nber, parts being brokenaway; Fig. 6 is a .iietail horizontal rsectional vi'ew taken on thelineIB-eGofFig-J; .1

Fig. Tis a detail View, partly in section; of the drive connections .betweenthe controls;

Referring to the drawing,-the numeral 40 designates a casing, :III .a .pump barrel, i=2 aplunger working in'the barrel, l 3 adisc-harge .valve,. |'4 'a spring for normally holding the valve 4 3 against its seat on the flanged seat -member', it a clamping nut for member Hand-barrel 1 l'having threaded engagement with the upper threaded end of a bore I1 in the casing .andbearing against a sealing gasket 18, IS a spring interposed between the barrel and a flange-- on the plunger and normally urging said plunger to 'a position in which its upper end uncovers an inlet port 2i in the barrel supplied'with fuel firom a manifold 22 whichis supplied from any suitable source of fuel-supply connected to the threaded passage 23. During its delivery stroke the.plunger i2 covers theinlet port 2| and forces the fuel in the barrel above the plunger past the spring loaded delivery or discharge valve [3 direct to a suitable injector if the device is of the so-called unit type or to piping supplying an injector mounted on the head or manifold of the engine if of the separate pump type.

The casing 10 is shown as formed of two parts secured together by screws 24, the upper carrying all the cylinders of a multi-cylinder pump and the lower the plunger operating mechanisms. As all of the pump units are the same, only one is shown in detail. 7

The lower'casing section has a top wall 25, 'a back wall 26, base 21, and a partition 28 dividing this section into two compartments 29 and 30 whose fronts are covered by a removable plate 3|. The top walli's apertured to receive a guide and plunger stop bushings 32 for each'pump unit and the partition similarly apertured for tappet guide bushings 33. The bushings 32 are clamped between the two sections of the casing while the bushings 33 are secured to the partitions in any suitable manner as by hold down bolts 34 and washers 34, as shown in Fig. 6.

The plunger actuator comprises a tappet member 35 having a slidably splined or keyed connection 35 with the inner wall of the bushing 33 and carrying a rotatable roller 36 yieldingly held by a spring 31 against a cam 38 formed on the cam shaft 39 driven by the engine 'or in cyclic synchronism therewith. The tappet has a forked upper end 40.

A flanged tubular socket member 4| has a bore 42 in which lower end of the plunger I2 is loosely mounted and against which the sprin l9 holds the flange 29 of the plunger in abutting engagement so as to act as a unit therewith. The flange 43 of the socket member abuts against the bushing 32 to limit the movement thereof, and the tubular portion of said member is slidably mounted in the bore of said bushing has a forked lower end 44.

The forked end 44 of the member 4 l is pivotally connected by a pin 44' with one end of a link 45 whose other end is pivctally connected by a pin 46 with the upper end of a link ll whose lower end is pivotally connected by a pin 48 with the forked end 4!] of the tappet member 35. The pin 46 may be formed integral with or connected to a roller 49 at one end and be in peened engagement with a roller 59 at its other end. The rollers 49 and 50 ride on the surface 5| of a rotatably shiftable stroke control member 52 which is mounted in the casing H) for angular adjustment.

The links 45 and 41 are during the return stroke of the actuator 35 urged to swing toward the control 52 under the action of a cam surface "53 on the link 41 engageable with a cooperative surface in the form of a fixed rod 54, and this cam action, as the actuator 35 is moved by its spring 31 to its initial position brings the rollers 49 and 50 normally into contact with said control, and to further insure this engagement thev control surface 5| is positioned so that the toggles are slightly out of line and biased toward said surface in the full stroke position of the 1 parts as shown in Fig. 1. As the control member 52 is turned, its control surface changes its angu larity relative to the rollers 49 and 55 with the result that as the actuator is moved inwardly on its pumping stroke, the toggle formed by the links and 41 will be bent to a position for breaking later or sooner in the stroke of the actuator depending upon the set position of the control surface 5|, and when the break does occur, the spring .IS quickly returns the plunger I? to its outer position independently of the actuator and of the speed of the engine. For no load the control surface 5i is set in the position shown in Fig. 3, and then during a very small part of the movement of the actuator 35 the knee of the toggle linkage is broken, and immediately the spring l9 brings the plunger and its associated member 4! back to the position shown in Fig. 3. Thereafter, the spring 3'? returns the actuator 35 and with it the links 45 and 47 which will be swung back to their initial position by the engagement of the cam surface 53 with the rod 54 as the actuator reaches its initial position. In the no-load position the movement of the plunger l2, if any, under the action of the control 52 is so slight that it does not cover the inlet port 2|, and consequently no fuel will be delivered past the discharge valve. Thus the changing of the angular position of the control member52 changes the stroke of the plunger l2 and hence the amount of fuel furnished by the pump through the stroke of the tappet 35 is constant. 7

- For a multi-cylinder pump the surface 5! for each pump unit is formed by notching the cylindrical shaft as shown in Fig. 5.

With stroke mechanism of the form above described, the stroke of the plunger starts with that of the actuator so that the time of beginning fuel injection is constant, and this has been found desirable on some engines. On other engines, particularly those of the direct injection type, it has been found advisable to delay the beginning of injection for part load charges of fuel, and during idling, over the time of injection of the full fuel charge and in the present instance means have been provided for this purpose comprising means for rotatably mounting the plunger l2, so that its obliquely inclined top or control edge 55 will change its position rela tive to the inlet port 2!, so that said port will be closed sooner or later during the stroke of the plunger l2. For rotating the plunger I have mounted it for free rotation relative to its socket member 4i and have provided a slidably keyed or splined connection 55 between its flange 26 recess 58 in the casing I 0 and is engaged by a rack 59 which reciprocates in a guide slot 50.

For a multi-cylinder engine the rack 59 engages the gear member 5'! of each pump unit, and. to provide for a single operating control I have shown in Fig. 7 a gearing connection between the rack 59 and the control member 52 comprising a shaft 5| journalled in suitable bearings in an end plate 62 of the machine and having a gear 63 meshing with saidrack and a screw gear 64 meshingwith its associated gear 65 on the control member 52, to turn said member through a relatively small angle to vary the stroke of the pump plungers [2 while turning the plungers themselves to vary the commencement of the injection period, so that for full charge of fuel the injection may commence earlier in 1 the cycle than for lighter charges. The control and a gear member 5'! which is mounted in a of the timing of the injection may be separately operated from the quantity control in some instances.

Pumps of the type above described have the advantage of simplicity of manufacture because only a plain cylindrical plunger and plain barrel are necessary, and this gives greater sealing surface than the scrolled relief plungers and a greater amount of time is available for the filling of the pump barrel because of the very quick return of the pump plunger by its return spring to its inlet position before and independent of its actuator.

, Where it is not necessary to vary the commencement of the injection period, the means for rotating the plunger l2' may be'omitted in which case the part 4| may be formed as an integral part of the pump plunger I2.

I desire it to be understood that this invention is not to be limited to any particular form or arrangement of parts except in so far as such limitations are included in the claims.

What I claim as my invention is:

1. In a fuel pump having a barrel having an inlet port, a pump plunger reciprocating in said barrel and rotatable relative to said barrel, and a spring for returning said plunger, the combination of an engine controlled reciprocatory actuator, a variable stroke drive connection between said actuator and said plunger to allow said plunger to be returned by said spring before and independently of said actuator, said plunger having an inclined control edge shiftable relative to said inlet port to control the beginning of fuel injection, and means for rotating said plunger.

2. In a fuel pump having a barrel provided with an inlet port, a pump plunger reciprocating in said barrel and rotatable relative thereto, and a spring for returning said plunger, the combination of an engine controlled reciprocatory actuator, a variable stroke drive connection between said actuator and said plunger to allow said plunger to be returned by said spring before and independently of said actuator, a shiftable control member for said variable stroke drive connection, said plunger having an inclined control edge shiftable relative to said inlet port to control the beginning of injection, means for rotating said plunger to shift said control edge, and means for simultaneously operating said plunger rotating means and said shiftable drive control member.

3. In a fuel pump having a barrel, a, pump plunger reciprocating in said barrel and a spring for returning said plunger, the combination of an engine controlled reciprocatory actuator, a

breakable toggle joint drive connection between said actuator and said plunger, and adjustable means to control the breaking of the knee of said toggle joint to vary the stroke of said pump plunger.

4. In a fuel pump having a barrel, a pump plunger reciprocating in said barrel and a spring for returning said plunger, the combination of an engine controlled reciprocatory actuator, a shiftable control member, a breakable toggle joint drive connection between said actuator and said plunger having its knee normally biased toward said control member, said control member being operable on the knee of said toggle joint to control its release.

5. In a fuel pump having a barrel, a pump plunger reciprocating in said barrel and a spring for returning said plunger, the combination with an engine controlled reciprocatory actuator, a breakable toggle joint drive connection between said actuator and said plunger, adjustable stroke control means operable to break the knee of the toggle joint during the delivery stroke of said actuator, and cam means engageable with a link of the toggle to reset the toggle joint during the return stroke of said actuator.

6. In a fuel pump having a barrel, a pump plunger reciprocating in said barrel, and a spring for returning said plunger, the combination of an engine controlled reciprocatory actuator, a releasable drive connection between said actuator and plunger, and a rotary shaft having a notch therein providing a control surface cooperating with said connection to control its release.

7. In a fuel pump having a barrel, a pump plunger reciprocating in said barrel and a spring for returning said plunger, the combination with an engine controlled reciprocatory actuator, a drive connection between said actuator and said plunger including a pair of toggle links, a rotatable stroke control member having a surface engaged by a part of the knee of said toggle links to break said knee during the delivery stroke of said actuator, one of said links having a cam surface and fixed means cooperating with said cam surface to reset the toggle joint during the return stroke of said actuator.

LOUIS O. FRENCH. 

